Plastic laminate body, manufacturing method of the same, and rear projection type image display apparatus

ABSTRACT

A manufacturing method of a plastic laminate body, the plastic laminate body having at least one plastic laminate member that is laminated on a plastic substrate, which plastic substrate is pre-processed in advance so as to have a substantially final configuration, the manufacturing method includes softening the plastic laminate member when a transfer surface of a mold member, which is pre-processed in advance so as to have a desired configuration, is transferred to a surface of the plastic laminate member, so that an excessive part of the plastic laminate member is moved to an escape part which is pre-formed at the plastic substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of application Ser. No.10/800,647, filed on Mar. 16, 2004, which claims priority to JapanesePatent Application Nos. 2003-378557, filed Nov. 7, 2003, and JP2003-077198, filed Mar. 20, 2003, the entire contents of each of whichare incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to plastic laminated bodies,manufacturing methods of the same, and rear projection type imagedisplay apparatuses, and more particularly, to a manufacturing method ofa plastic laminate body such as a composite plastic molding article madeby laminating a plurality of plastics, an optical element having atransfer surface (reflection surface) having high precision like aplastic reflection mirror, or the like.

2. Description of the Related Art

As a method and an apparatus by which two members are laminated and atransfer surface is transferred to one of the members, there are thecontact bonding method and the apparatus shown in Japanese Laid-OpenPatent Application No. 1-316702. In the method and apparatus, a lenssheet part is heated and made molten so as to be developed and extendedon a lens mold surface, and then a translucent member is contact-bonded.In this method, it is necessary to make the lens sheet thick in order tocover the curvature in a case where a subject configuration is a curvedsurface. Because of this, it is required to take a lot of time forheating, melting, and solidifying the lens sheet, and this causesincreasing cost. Furthermore, thicknesses of some parts of the lenssheet become uneven, and therefore it is difficult to apply pressure tothe entire transfer surface evenly. Because of this, as shown in FIG. 2,an uneven contraction occurs after the contact bonding process andtherefore it is difficult to manufacture a molded article with highprecision.

In Japanese Laid-Open Patent Application No. 3-82513, Japanese Laid-OpenPatent Application No. 5-154933, Japanese Laid-Open Patent ApplicationNo. 7-178834, and Japanese Laid-Open Patent Application No. 2000-326360,a method for providing a reflection film, where a metal layer is formedin advance in a mold, then injecting and filling a resin from a backsurface of the reflection film so as to unify, is suggested. In thiscase, the film has to be fixed in the mold in order to prevent wrinklesfrom being generated and therefore the mold structure is complex.Furthermore, if it is attempted to make the film correspond to a curvedsurface, the film is adversely influenced by high temperature at thetime of resin injection and flow pressure on the assumption ofuniformity by injection molding. This causes generation of wrinkles andtears of the film. If the molded article is made thick for securingstrength of the molded article, it takes more time for cooling and themolding cycle increases. Furthermore, if the thickness of the moldedarticle is not uniform, pressure at the thick wall part and pressure atthe thin wall part do not become uniform, so that it is difficult tosecure high configuration precision only by injection molding.

In Japanese Patent No. 2831959, first, more than two plastic basematerials prepared in advance are inserted into the mold, and a transferdue to self expansion and uniformity are realized by heating at atemperature higher than a softening temperature of the plastic basematerials. Next, the plastic base materials are cooled so as to have atemperature less than a heat deformation temperature and then pulledout. In this case, although there is no influence of unevenness of resinpressure and resin flow, it takes a lot of time for molding because allof the base material is heated and cooled. This causes an increase ofcost.

There is a unifying way by heat contact bonding that can prevent theabove-discussed influence by the resin flowing and the increase of themolding cycle, comprising a manufacturing method of a plastic laminatebody such as a composite plastic molding article made by laminating aplurality of plastics, including an optical element having a transfersurface (reflection surface) having high precision, such as a plasticreflection mirror.

However, according to the related art unifying way by heat contactbonding, there are the following problems in a case where the subjectconfiguration includes a curved surface.

FIG. 1 is a schematic view showing a related art manufacturing method ofa plastic laminate body. More specifically, related art wherein twomembers are bonded in one body by heat contact bonding and a transfersurface is transferred to either of the members, is shown in FIG. 1. Athermal plastic material 3 is heated and melted on a lower mold member 2having a transfer surface 1 in advance by a heater 4. And then, an uppermold member 6 is lowered down on the lower mold member 2 via thesubstrate 5 so as to pressurize (See FIG. 1-(A)) and therefore thethermal plastic material 3 and the substrate 5 are contact-bonded (SeeFIG. 1-(B)). In this case, as shown in FIG. 1, since the desiredconfiguration contains a curved surface, the thickness of the thermalplastic material 3 is different depending on parts indicated by marks“A” and “B”. As a result of this, a pressure distribution (non-uniformpressure distribution) occurs at the time of pressuring so that a loadcannot be given to the entire transfer surface. Because of this, acontraction after contact bonding becomes uneven so that it is difficultto transfer the transfer surface 1 of the mold member 2 to a surface ofa laminate body 7 with high precision.

FIG. 2 is a schematic view of another example of the related artmanufacturing method of the plastic laminate body. More specifically, acase where the substrate 5 is processed in advance to be curved is usedfor pressurizing is shown in FIG. 2. In this case, however, as shown inFIG. 2, if the substrate 5 and the lower mold member 2 having thetransfer surface 1 are not positioned with high precision, the thicknessof the thermal plastic material 3 is different depending on partsindicated by marks “C” and “D”. Hence, it is still difficult tosufficiently reduce the pressure distribution at the time of pressuring.In addition, even if the substrate 5 and the lower mold member 2 havingthe transfer surface 1 are positioned with high precision, in a casewhere configuration error between the substrate 5 and the transfersurface 1 of the lower mold member 2 differs depending on positions,there is still uneven pressure distribution like the case shown in FIG.1.

That is, if particularly the desired configuration is a curved surface,there is an uneven pressure distribution at the time of pressurizing dueto the configuration error of the plastic substrate and the memberhaving the transfer surface, so that the contraction after contactbonding becomes uneven. This causes a problem in that it is difficult totransfer the transfer surface with high precision.

SUMMARY OF THE INVENTION

Accordingly, it is a general object of the present invention to providea novel and useful plastic laminate body, manufacturing method of thesame, and a rear projection type image display apparatus in which one ormore of the problems described above are eliminated.

Another and more specific object of the present invention is to providea structure wherein a pressure distribution problem is solved by anescape part. More specifically, the present invention is directed to aplastic laminate body, manufacturing method of the same, and a rearprojection type image display apparatus, wherein an escape part, wherean excessive part of the laminate member is moved is formed at a plasticsubstrate in advance, the laminate member is heated and softened, andthe excessive part of the laminate member is moved to the escape part.As a result of this, the distribution problem can be solved so that thepressure is made even and therefore surface transferring with highprecision can be realized.

The above objects of the present invention are achieved by amanufacturing method of a plastic laminate body, the plastic laminatebody having at least one plastic laminate member that is laminated on aplastic substrate, which plastic substrate is pre-processed in advanceso as to have a substantially final configuration, the manufacturingmethod including:

softening the plastic laminate member when a transfer surface of a moldmember, which is pre-processed in advance so as to have a desiredconfiguration, is transferred to a surface of the plastic laminatemember, so that an excessive part of the plastic laminate member ismoved to an escape part which is pre-formed at the plastic substrate.

In the manufacturing method, the transfer surface of the mold member maybe pushed to the plastic laminate member with pressure so that thetransfer surface of the mold member is transferred to the surface of theplastic laminate member.

According to the above mentioned invention as described above, it ispossible to reduce a pressure distribution at the time of pressurizingand realize surface transferring with high precision, by movingexcessive resin of the plastic laminate member to the escape part of thesubstrate.

In the manufacturing method, the plastic substrate may have a honeycombstructure, and an opening part of the honeycomb structure may be formedas the escape part to which the excessive part of the plastic laminatemember is moved.

According to the above mentioned invention as described above, it isfurther possible to secure rigidity of the plastic laminate body andreduce the weight of the plastic laminate body.

In the manufacturing method, the plastic substrate may have a honeycombstructure,

a thin wall part may be formed at a side of a laminate surface of theplastic laminate member, of an opening part of the honeycomb structure,and

the escape part, to which the excessive part of the plastic laminatemember is moved, may be formed by deforming the thin wall part accordingto pressure loaded at the time when the mold member is pushed with thepressure.

According to the above mentioned invention as described above, the thinwall part formed at the opening part having the honeycomb configurationis modified and the excessive resin of the plastic laminate member ismoved to the thin part, so that the excessive resin does not continuemoving to the opening part and therefore the pressure distribution canbe reduced stably without being influenced by the degree of viscosity.

In the manufacturing method, a thickness of the thin wall part may beequal to or more than 10 μm and equal to or less than 500 μm.

According to the above mentioned invention as described above, the thinwall part is prevented from being broken at the time when the plasticlaminate member and the plastic substrate are bonded in one body and adeformation for easing the pressure distribution can be made, by makingthe thickness of the thin wall part equal to or more than 10 μm andequal to or less than 500 μm.

In the manufacturing method, the plastic substrate having the honeycombstructure may be formed by filling a mold with a molten resin at highpressure, wherein a plurality of pins for forming the honeycombstructure at a cavity are provided.

According to the above mentioned invention as described above, it ispossible to easily manufacture the substrate at low cost by injectionmolding.

In the manufacturing method, gas may be given to an interface of thepins and the resin before the pins provided in the cavity of the moldare pulled out from the resin filling the cavity.

According to the above mentioned invention as described above, it ispossible to reduce mold release resistance at the time of mold releasingwhen the substrate is manufactured by injection molding, and thereforeit is possible to prevent a deformation at the time when the substratehaving the honeycomb configuration is released from the mold.

In the manufacturing method, the plastic substrate may be formed by aporous body, and

a porous part of the porous body may be formed as the escape part towhich the excessive part of the plastic laminate member is moved.

According to the above mentioned invention as described above, since theplastic substrate is formed by a porous body, it is possible to easilymanufacture the substrate at a low cost.

In the manufacturing method, the plastic substrate may be formed byincluding a foaming material when the plastic substrate is molded.

According to the above mentioned invention as described above, since theplastic substrate is formed by including a foaming material when theplastic substrate is molded, it is possible to easily manufacture thesubstrate formed by the porous body at a low cost.

In the manufacturing method, the plastic laminate member may be softenedat the time when the mold member is pushed with pressure, so that asubstantial final and desired surface configuration of the plasticsubstrate is corrected and the plastic laminate member and the plasticsubstrate are bonded in one body.

According to the above mentioned invention as described above, theplastic laminate member is softened at the time of pressurizing so thata surface configuration of the substrate is corrected to a transfersurface configuration (the substantial final and desired surfaceconfiguration) of the mold member, surface transferring can be done withhigh precision, and the plastic laminate member and the plasticsubstrate are strongly bonded in one body.

In the manufacturing method, a plastic intermediate layer may beinserted between the plastic laminate member and the plastic substrate,and the plastic intermediate layer may be softened at the time when themold member is pushed with pressure, so that a substantial final anddesired surface configuration of the plastic substrate is corrected andthe plastic laminate member and the plastic substrate are bonded in onebody.

According to the above mentioned invention as described above, theplastic intermediate layer is inserted between the plastic laminatemember and the plastic substrate, and the plastic intermediate layer issoftened at the time of pressurizing so that the plastic laminate memberand the plastic substrate can be bonded in one body without softeningthe laminate body and therefore a function can be added to the laminatemember in advance.

In the manufacturing method, a structural member of the plastic laminatemember may be formed by a thermoplastic member whose softeningtemperature T1 is lower than a softening temperature T2 of a structuralmember of the plastic substrate, and

the plastic laminate member may be heated so as to have a temperatureequal to and more than the softening temperature T1 and equal to andless than the softening temperature T2 when the mold member is pushedwith the pressure after the plastic laminate member is laminated on alaminate surface of the plastic substrate, so that the plastic laminatemember and the plastic substrate are bonded in one body.

In the manufacturing method, a structural member of the plasticintermediate layer may be formed by a thermoplastic member whosesoftening temperature T3 is lower than a softening temperature T2 of astructural member of the plastic substrate, and

the plastic laminate member may be heated so as to have a temperatureequal to or more than the softening temperature T3 and equal to or lessthan the softening temperature T2 when the mold member is pushed withthe pressure after the plastic intermediate layer and the plasticlaminate member are laminated in turn on a laminate surface of theplastic substrate, so that the plastic laminate member and the plasticsubstrate are bonded in one body.

According to the above mentioned invention as described above, theplastic laminate member and the plastic substrate can be strongly bondedin one body without softening the laminate body, and therefore it ispossible to shorten the processing cycle at the time when the plasticlaminate member and the plastic substrate are being bonded in one body.

In the manufacturing method, a structural member of the plastic laminatemember may be formed by an ultraviolet curing type resin and

an ultraviolet light may be applied when the mold member is pushed withthe pressure after the plastic laminate member is laminated on alaminate surface of the plastic substrate, so that the plastic laminatemember and the plastic substrate are bonded in one body.

In the manufacturing method, a structural member of the plasticintermediate layer may be formed by an ultraviolet curing type resin and

an ultraviolet light may be applied when the mold member is pushed withthe pressure after the plastic intermediate layer and the plasticlaminate member are laminated in turn on a laminate surface of theplastic substrate, so that the plastic laminate member and the plasticsubstrate are bonded in one body.

According to the above mentioned invention as described above, thestructural member of the plastic laminate member or the intermediatelayer is formed by the ultraviolet curing type resin, the laminatemember is laminated on the laminate surface of the substrate, and theultraviolet light is applied at the time of pressuring, so that theplastic laminate member and the plastic substrate are bonded in onebody. Hence, heating and cooling processes are not necessary andtherefore it is possible to shorten the processing cycle.

In the manufacturing method, structural members of the plastic substrateand the plastic laminate member may be formed under conditions that amultiplied result of a dielectric constant E and a dielectric tangent δof the plastic substrate is smaller than 0.01, namely ε×tan δ<0.01, anda multiplied result of a dielectric constant ε′ and a dielectric tangentδ′ of the plastic laminate member is larger than 0.01, namely0.01<ε′×tan δ′, and

the plastic laminate member may be softened by a high frequencydielectric heating process, when the mold member is pushed with thepressure after the plastic laminate member is laminated on a laminatesurface of the plastic substrate, so that the plastic laminate memberand the plastic substrate are bonded in one body.

In the manufacturing method, structural members of the plastic substrateand the plastic laminated member or the plastic intermediate layer maybe formed under conditions that a multiplied result of a dielectricconstant ε and a dielectric tangent δ of the plastic substrate issmaller than 0.01, namely ε×tan δ<0.01, and a multiplied result of adielectric constant ε′ and a dielectric tangent δ′ of the plasticlaminated member or the plastic intermediate layer is larger than 0.01,namely 0.01<ε′×tan δ′, and

the plastic laminate member or the plastic intermediate layer may beselectively softened by a high frequency dielectric heating process,when the mold member is pushed with the pressure after the plasticintermediate layer and the plastic laminate member are laminated in turnon a laminate surface of the plastic substrate, so that the plasticlaminate member and the plastic substrate are bonded in one body.

According to the above mentioned invention as described above,structural members of the plastic substrate and the plastic laminatedmember or the plastic intermediate layer are formed under conditionsthat the multiplied result of the dielectric constant δ and thedielectric tangent δ of the plastic substrate is smaller than 0.01,namely ε×tan δ<0.01, and the multiplied result of the dielectricconstant ε′ and the dielectric tangent δ′ of the plastic laminatedmember or the plastic intermediate layer is larger than 0.01, namely0.01<ε′×tan δ′, the plastic laminate member is laminated on the laminatesurface of the substrate, and only the plastic laminate member orplastic intermediate layer is softened by the high frequency dielectricheating process at the time of pressurizing. As a result of this, theplastic laminate member and the plastic substrate are bonded in onebody, and selective heating process can be applied. Furthermore, sinceheating response is extremely rapid, it is possible to shorten theprocessing cycle.

In the manufacturing method, the plastic intermediate layer may beformed by a heat curing type bonding member whose bonding temperature islower than a softening temperature of the plastic substrate or a hotmelt type bonding member, and

a heating or pressurizing process may be applied so that the plasticlaminate member and the plastic substrate are bonded in one body.

According to the above mentioned invention as described above, theplastic laminate member and the plastic substrate can be strongly bondedin one body without softening the laminate body.

In the manufacturing method, the plastic laminate member may be formedby a plastic film having a thickness equal to or less than 0.5 mm.

According to the above mentioned invention as described above, it ispossible to easily modify the laminate member so as to have a desiredconfiguration. Furthermore, in a case where a function is applied to thelaminate member in advance, the laminate member can be used as forming aroll. Therefore, the function can be easily given at low cost.

The above object of the present invention is also achieved by a plasticlaminate body manufactured by a manufacturing method, the plasticlaminate body having at least one plastic laminate member that islaminated on a plastic substrate, which plastic substrate ispre-processed in advance so as to have a substantially finalconfiguration, the manufacturing method including:

softening the plastic laminate member when a transfer surface of a moldmember, which is pre-processed in advance so as to have a desiredconfiguration, is transferred to a surface of the plastic laminatemember, so that an excessive part of the plastic laminate member ismoved to an escape part which is pre-formed at the plastic substrate,

wherein a metal reflection film is pre-formed on a surface of theplastic laminate member.

According to the above mentioned invention as described above, it ispossible to provide a plastic mirror having a light weight at low castand with high precision and rigidity by manufacturing the reflectionmirror with the above mentioned manufacturing method.

The above object of the present invention is also achieved by a rearprojection type image display apparatus, including:

a plastic laminate body which is used as a projecting mirror, theplastic laminate body having at least one plastic laminate member thatis laminated on a plastic substrate, which plastic substrate ispre-processed in advance so as to have a substantially finalconfiguration, the plastic laminate body being manufactured by amanufacturing method, including:

softening the plastic laminate member when a transfer surface of a moldmember, which is pre-processed in advance so as to have a desiredconfiguration, is transferred to a surface of the plastic laminatemember, so that an excessive part of the plastic laminate member ismoved to an escape part which is pre-formed at the plastic substrate,

wherein a metal reflection film is pre-formed on a surface of theplastic laminate member.

According to the above mentioned invention as described above, it ispossible to manufacture a rear projection type image display apparatushaving high image quality and low weight at a low cost.

Other objects, features, and advantages of the present invention willbecome more apparent from the following detailed description when readin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing a related art manufacturing method ofa plastic laminate body;

FIG. 2 is a schematic view of another example of the related artmanufacturing method of the plastic laminate body;

FIG. 3 is a schematic view showing a structure of a plastic laminatebody and a manufacturing method of the same of a first embodiment of thepresent invention;

FIG. 4 is an enlarged view of a main part of a honeycomb-shapedsubstrate of the plastic laminate body shown in FIG. 3;

FIG. 5 is a schematic view showing another example of a modifying methodof the laminate member provided at the plastic laminate body of thefirst embodiment of the present invention;

FIG. 6 is a schematic view showing other example of a modifying methodof the laminate member provided at the plastic laminate body of thefirst embodiment of the present invention;

FIG. 7 is a schematic view if a honeycomb-shaped substrate provided at aplastic laminate body of a second embodiment of the present invention;

FIG. 8 is a schematic view showing a structure of a plastic laminatebody and a manufacturing method of the same of the second embodiment ofthe present invention;

FIG. 9 is an enlarged view of a main part of a honeycomb-shapedsubstrate of the plastic laminate body shown in FIG. 8;

FIG. 10 is a schematic view showing a manufacturing method of ahoneycomb-shaped substrate used for the plastic laminate body of thepresent invention;

FIG. 11 is an enlarged view of a main part of a mold used formanufacturing a honeycomb-shaped substrate shown in FIG. 10;

FIG. 12 is a schematic view showing another example of a modifyingmethod of the laminate member provided at the plastic laminate body ofthe second embodiment of the present invention;

FIG. 13 is a schematic view showing other example of a modifying methodof the laminate member provided at the plastic laminate body of thesecond embodiment of the present invention;

FIG. 14 is a schematic view showing a structure of a plastic laminatebody and a manufacturing method of the same of a third embodiment of thepresent invention;

FIG. 15 is a schematic view showing a structure of a plastic laminatebody and a manufacturing method of the same of a fourth embodiment ofthe present invention;

FIG. 16 is a view showing a cross-sectional structure of a plasticreflection mirror manufactured by the manufacturing method of theplastic laminate body of the present invention;

FIG. 17 is a schematic view showing a structure of a laminate unifyingapparatus used for a manufacturing method of a plastic laminate body ofa fifth embodiment of the present invention;

FIG. 18 is a schematic view showing a structure of a laminate unifyingapparatus used for a manufacturing method of a plastic laminate body ofa sixth embodiment of the present invention; and

FIG. 19 is a schematic view of a real projection type image displayapparatus having the plastic reflection mirror shown in FIG. 16.

DETAILED DESCRIPTION OF THE PREFERED EMBODIMENTS

A description will now be given, with reference to FIG. 3 through FIG.19, of embodiments of the present invention.

FIG. 3 is a schematic view showing a structure of a plastic laminatebody and a manufacturing method of the same of a first embodiment of thepresent invention. As shown in FIG. 3, an upper mold member 6 and alower mold member 2 are provided so as to face each other. A transfersurface 1 having at least one desired configuration is formed at thelower mold member 2. A heater 4 for heating is provided in the lowermole member 2. A film-shaped laminate member 8 made of an acrylic resinis fixed on the lower mold member 2. A honeycomb-shaped substrate 9 isinserted between the laminate member 8 and the upper member 6 having thetransfer surface 1. See FIG. 3-(A). The substrate 9 is processed inadvance so that a surface of the substrate 9 is a substantially finaldesired configuration. In this embodiment, a polycarbonate resin whosesoftening temperature is approximately 150 □ is used as a structuralmember of the honeycomb-shaped substrate 9, and an acrylic resin whosesoftening temperature is 105 □ is used as a structural member of thelaminate member 8.

Next, an operation in the first embodiment is discussed. The upper moldmember 6 is lowered down in a state shown in FIG. 3-(A). At this time,the film-shaped laminate member 8 is pushed with pressure by thehoneycomb-shaped substrate 9 so as to have a curved surfaceconfiguration. Next, the laminate member 8 comes in contact with thetransfer surface 1 of the lower mold member 2. Finally, two members,namely the honeycomb substrate 9 and the laminate member 8, arepressurized and bonded. See FIG. 3-(B). At this time, a heating processis done at 120 □, which is higher than the softening temperature of theacrylic resin forming the laminate member 8 and lower than softeningtemperature of the polycarbonate resin forming the honeycomb-shapedsubstrate 9, by the heater 4 provided in the lower mold member 2. Next,after a cooling process is done at 100 □ that is lower than thesoftening temperature of the acrylic resin, the upper mold member 6 israised so that the unified laminate body 7 is picked out. See FIG.3-(C).

Next, an advantage of the first embodiment of the present invention isdiscussed. According to the first embodiment of the present invention,even if the thickness of the laminate body 8 at the time of pressuredbecomes uneven as shown in FIG. 1 and FIG. 2 due to a position gap ofthe transfer surface 1 of the lower mold member 2 and the honeycombsubstrate 9 or a configuration error depending on position, theexcessive resin of the laminate member 8 is moved to the opening part10, which is an escape part of the honeycomb-shaped substrate 9, so thatthe pressure distribution occurring at the time of pressuring can beeased. Hence, it is possible to realize a transfer with high precision.

Referring to FIG. 4, details of the above mentioned advantage of thefirst embodiment of the present invention are now discussed.

FIG. 4 is an enlarged view of parts corresponding to a part where thelaminate member 8 is made thin, shown by a mark “E” in FIG. 3-(B), atthe time of pressuring and a part where the laminate member 8 is madethick, shown by a mark “F” in FIG. 3-(B), at the time of pressuring. Atthe thinned part shown by the mark “E” wherein loaded pressure becomeslarge, a lot of the resin of the laminate member 8 is moved to theopening part 10 of the honeycomb substrate 9, so that the abovementioned pressure is reduced. At the thickened part shown by the mark“F” wherein loaded pressure becomes small, the amount of the resin movedto the opening part 10 of the honeycomb substrate 9 becomes small. Thatis, the amount of the resin moved to the opening part 10 of thehoneycomb substrate 9 is changed depending on the loaded pressure, andtherefore an even pressure as a whole is loaded.

In this embodiment, a plane shape film is used as the laminate member 8and the laminate member 8 is deformed at the same time of pressurizing.However, a method for deforming the laminate member 8 to the desiredconfiguration in the present invention is not limited to thisembodiment. For example, as shown in FIG. 5, the laminate member 8 maybe deformed to a configuration of the transfer surface 1 in advance. Inthis case, the laminate member 8 may be deformed to a configuration ofthe transfer surface 1 in advance by means of vacuum suction, forexample.

Furthermore, as shown in FIG. 6-(A), a liquid resin 11 is inserted intothe lower mold member 2 in advance and then the honeycomb-shapedsubstrate 9 comes in contact with the liquid resin 11 (at this time, theexcessive resin moves to the escape part) so that they can be made solidand uniform. In a case where the thermal plastic resin is used as thelaminate member as discussed in the first embodiment, a liquid memberthat is heated and melted in advance is inserted into the lower moldmember. However, the present invention is not limited the abovementioned example. For example, a thermal solid resin that is in aliquid state at a normal temperature may be used. In this case, afterthe honeycomb-shaped substrate 9 comes in contact with the thermal solidresin, the thermal plastic resin can be made solid by heating.Furthermore, as shown in FIG.6-(B), the liquid state resin 11 may beinserted in the gap D after the transfer surface 1 and the honeycombsubstrate 9 are faced so as to make a desired distance D between thetransfer surface 1 and the honeycomb substrate 9.

Here, advantages, other than reduction of the pressure distribution, ofthe first embodiment of the present invention are discussed.

First, it is possible to correct a configuration of the honeycombsubstrate 9 by melting the laminate member 8. Hence, it is possible totransfer the transfer surface 1 precisely. High precision of thehoneycomb substrate 9 is not necessary and therefore it is possible toreduce cost.

Second, since only the laminate member 8 is heated and melted, it ispossible to shorten the time for heating and cooling so that the moldingcycle can be reduced. As for the thickness of the laminate member 8,only a thickness more than the configuration error of thehoneycomb-shaped substrate 9 and the lower mold member 2 is required.Hence, if the honeycomb-shaped substrate 9 is processed so as to have asubstantially final configuration, the above mentioned thickness can bereduced.

Third, since the substrate 9 has a honeycomb configuration, it ispossible to reduce the weight of the substrate 9 while keeping rigidityof the laminate body.

FIG. 7 is a schematic view of a honeycomb-shaped substrate provided at aplastic laminate body of a second embodiment of the present invention.More specifically, FIG. 7-(A) is a cross-sectional view of the substrateand FIG. 7-(B) is a back view of the substrate. FIG. 8 is a schematicview showing a structure of a plastic laminate body and a manufacturingmethod of the same of the second embodiment of the present invention.

A honeycomb-shaped substrate 9 has an escape part for the excessiveresin of the laminate member 8 as shown in FIG. 7. Namely, a thin wallpart 12, as an escape part, is formed at a surface where the laminatemember 8 is laminated, of the opening part 10 formed in thehoneycomb-shaped substrate 9. That is, only whether the thin wall part12 is provided is the difference between the honeycomb-shaped substrateshown in FIG. 7 and the honeycomb-shaped substrate shown in FIG. 3. Therest of the structure of the honeycomb-shaped substrate shown in FIG. 7is substantially the same as the rest of the structure of thehoneycomb-shaped substrate shown in FIG. 3.

As shown in FIG. 8, the plastic laminate body can be manufactured byusing the honeycomb-shaped substrate 9 shown in FIG. 7 in a similar wayto the way shown in FIG. 3. In this case, a pressure distributiongenerated at the time of pressurizing by deforming the thin wall part 12of the honeycomb-shaped substrate 9 is eased and therefore a transferwith high precision can be realized.

Referring to FIG. 9, detail of the above mentioned advantage of thesecond embodiment of the present invention are now discussed.

FIG. 9 is an enlarged view of parts corresponding to a part where thelaminate member 8 is made thin, shown by a mark “E” in FIG. 8-(B), atthe time of pressuring, and a part where the laminate member 8 is madethick, shown by a mark “F” in FIG. 8-(B), at the time of pressuring. Atthe thinned part shown by the mark “E” wherein the loaded pressurebecomes large, the thin wall part 12 is largely deformed and theexcessive resin is moved there, so that the above mentioned pressure isreduced. At the thickened part shown by the mark “F” wherein the loadedpressure becomes small, the amount of deformation of the thin wall part12 is small and amount of the resin moved there becomes small. That is,the amount of deformation of the thin wall part 12, namely the amount ofthe resin moved, is changed depending on the loaded pressure, andtherefore an even pressure as a whole is loaded.

Compared to the first embodiment, in the second embodiment, themanufacturing method of the substrate may be difficult. However, sincethe excessive resin is blocked by the thin wall part 12 and thereforedoes not continue moving to the opening part 10, the pressuredistribution can be reduced stably without being influenced by thedegree of viscosity. It is preferable that the thin wall part 12 has athickness between 10 μm and 500 μm. If the thin wall part 12 has athickness less than 10 μm, it is difficult to manufacture-process, and acrack may be generated by pressurizing at the time of unifying. Inaddition, if the thin wall part 12 has a thickness more than 500 μm, itis difficult to modify sufficiently at the time of pressurizing.

FIG. 10 is a schematic view showing a manufacturing method of theabove-discussed honeycomb-shaped substrate 9. Although a manufacturingmethod of the honeycomb-shaped substrate 9 where the thin wall part 12is formed is shown in this example, this method can be applied to ahoneycomb substrate 9 where a thin wall part is not formed. As shown inFIG. 10-(A), a polycarbonate resin molten in a cylinder is injected intoand fills a mold 15 whose temperature is kept 130 □, which is atemperature less than the softening temperature of the resin, where aplurality of pins 14 are formed for forming a honeycomb structure in acavity. After the polycarbonate resin is cooled at a temperature lessthan the softening temperature, the honeycomb-shaped substrate 9 ispicked out from the mold 15. See FIG. 10-(B).

FIG. 11 is an enlarged view of one of the pins 14 formed in the cavityof the mold 15. A minute hole 16, connecting to a compressed gas supplysource (not shown in FIG. 11) provided outside, is formed at a head endof the pin 14. Before the pin 14 is released from the mold, gas isprovided from the hole 16.

Advantages of manufacturing the honeycomb substrate 9 are now discussed.

First, the manufacturing process can be done by normal injectionmolding. Hence the manufacturing process can be done easily and at lowcost. As described above, in this embodiment, it is possible to correctthe configuration at the time of unifying and therefore precision of thesurface of the honeycomb-shaped substrate is not required.

Second, gas is provided from the pin 14 for forming the opening part 10at a lower part of the thin wall part 12, so that an air layer is formedbetween the pin 14 and the resin at the time of mold releasing.Therefore, mold release resistance of the resin and pin 14 at the timeof mold releasing is reduced and deformation at the time of moldreleasing of the honeycomb-shaped substrate 9 can be prevented.

By making a side surface of the pin 14 have a taper configuration 17 asshown in FIG. 11, the mold release resistance of the resin and pin 14the time of mold releasing is reduced and deformation at the time ofmold releasing of the honeycomb-shaped substrate 9 can be prevented.

A porous plastic can be used as a material where the escape part for theexcessive resin of the laminate member 8 is formed. In this case, it isnot necessary to form the opening part 10 of the honeycomb-shapedsubstrate 9 as described above, that is, it is not necessary to deviseto pull pins, by including a foaming material. Hence, it is possible tomanufacture the substrate where the escape part for the excessive resinof the laminate member 8, more easily.

In the first and second embodiments, a two-layer structure of thehoneycomb-shaped substrate 9 and the laminate member 8 is discussed.Here, as a third embodiment of the present invention, a three-layersstructure is discussed with reference to FIG. 14.

As shown in FIG. 14, a film-shaped laminate member 8, formed by apolyethylene terephthalate resin whose softening temperature is 260 □,is fixed on a lower mold member 2. An intermediate layer 18 formed by aurethane resin whose softening temperature is 110 μ, is laminated at theside of the laminate surface of a honeycomb-shaped substrate 9, whichside faces the film-shaped laminate member 8. The honeycomb-shapedsubstrate 9 is inserted between the intermediate layer 18 and an uppermold member 6, as shown in FIG. 14-(A). Although the honeycomb-shapedsubstrate 9 not having a thin wall part is used in this embodiment, thepresent invention is not limited to this honeycomb-shaped substrate 9. Ahoneycomb-shaped substrate having a thin wall part 12 may be used and aporous substrate may be used.

Next, an operation in the third embodiment is discussed. The upper moldmember 6 is lowered down in a state shown in FIG. 14-(A). At this time,as in the first embodiment, the film-shaped laminate member 8 is pushedwith pressure by the honeycomb-shaped substrate 9 so as to have a curvedsurface configuration. Next, the laminate member 8 comes in contact withthe transfer surface 1 of the lower mold member 2. Finally, two members,namely the honeycomb-shaped substrate 9 and the laminate member 8, arepressurized and bonded. See FIG. 14-(B). At this time, a heating processis done at 130 □ that is higher than the softening temperature of theurethane resin forming the intermediate layer 18 and lower than thesoftening temperature of the polyethylene terephthalate resin formingthe honeycomb-shaped substrate 9, by the heater 4 provided in the lowermold member 2. Next, after a cooling process is done at 100 □ that islower than the softening temperature of the urethane resin, the uppermold member 6 is raised so that the unified laminate body 7 is pickedout. See FIG. 14-(C).

Next, an advantage of the third embodiment of the present invention isdiscussed. According to the third embodiment of the present invention,it is possible to ease the pressure distribution generated at the timeof pressurizing so that a transfer with high precision can be realized.Furthermore, a substrate configuration can be corrected by melting theintermediate layer 18 so that the transfer surface 1 can be transferredprecisely. The big difference regarding the advantage between thisembodiment and the first or second embodiment is that, in thisembodiment, it is possible to correct the configuration of the substrateand perform contact bonding of the laminate member 8, without meltingthe laminate member 8. In this case, it is possible to add a functionsuch as a metal reflection film or a non-reflection coating to thelaminate member 8 in advance. That is, since the laminate member 8 isnot molten, even if the above-mentioned function is added to thelaminate member 8, the function is not lost by unifying. For example, alarge type curved surface mirror can be manufactured at low cost withouta later vapor deposition process as shown in FIG. 16, by using areflection film wherein the metal reflection film 19 is formed on thelaminate member 8 in advance. As for adding a function to the laminatemember 8 before it has been unified, it is possible to perform acontinuous process such as roll shape winding. As compared with adding afunction to the laminate member 8 after it has been unified, namely abatch process, cost for adding a function before the unifying process isless. In addition, if the laminate member is formed by a film less than0.5 mm thickness, it is possible to easily deform the laminate member.Although in this embodiment, urethane resin is used for the intermediatelayer 18, a hot melt type or thermal solid type bonding sheet may beused so that strong adhesion can be achieved. Manufacturing methods andplastic laminate bodies discussed in other embodiments can be applied tothe large type curved surface mirror shown in FIG. 16.

FIG. 15 is a schematic view showing a structure of a plastic laminatebody and a manufacturing method of the same of a fourth embodiment ofthe present invention. The fourth embodiment is substantially the sameas the third embodiment, but is different from the third embodiment onlyin that a honeycomb-shaped substrate having the thin wall part 12 isused in the fourth embodiment.

FIG. 17 is a schematic view showing a structure of a laminate unifyingapparatus used for a manufacturing method of a plastic laminate body ofa fifth embodiment of the present invention. Although thehoneycomb-shaped substrate having the thin wall part of the secondembodiment shown in FIG. 17 and FIG. 18 is described below, thehoneycomb-shaped substrate not having the thin wall part of the firstembodiment may also be used in this embodiment.

Here, only the difference between this embodiment and the first orsecond embodiment in the case of the two-layers structure of thelaminate member 8 and the honeycomb-shaped substrate 9 discussed in thefirst or second embodiment is discussed. An ultraviolet solid type resin20 is inserted in the cavity where a transfer surface 1 of the lowermold member 2 formed by ultraviolet permeable quartz is formed.

The honeycomb-shaped substrate 9 is inserted between the above-mentionedlower mold member 2 and the upper mold member 6. See FIG. 17-(A). Anultraviolet irradiation apparatus 21 is provided at a lower part of thelower mold member 2 so that an ultraviolet light can be applied to theultraviolet solid type resin 20.

Next, an operation in the fifth embodiment is discussed. The upper moldmember 6 is lowered down in a state shown in FIG. 17-(A). Thehoneycomb-shaped substrate 9 comes in contact with the ultraviolet solidtype resin 20, and both of them are pressurized and bonded. See FIG.17-(B). At this time, the ultraviolet light can be applied to theultraviolet solid type resin 20 via the lower mold member 2 by theultraviolet irradiation apparatus 21 provided at a lower part of thelower mold member 2. As a result of this, the ultraviolet solid typeresin 20 is made solid, and adhered to and unified with thehoneycomb-shaped substrate 9. Next, the upper mold member 6 is raised sothat the unified laminate body 7 is picked out. See FIG. 17-(C).

Next, an advantage of the fifth embodiment of the present invention isdiscussed. According to the fifth embodiment of the present invention,as well as the first and second embodiments, it is possible to ease thepressure distribution generated at the time of pressurizing by theexcessive resin of the laminate member 8 escaping to the opening part 10or thin wall part 12 of the honeycomb-shaped substrate 9, and therebytransfer with high precision can be realized.

Furthermore, in this embodiment, it is possible to correct the surfaceconfiguration of the honeycomb-shaped substrate 9 by the ultravioletsolid resin 20, and thereby the transfer surface 1 can be transferredprecisely. The big difference regarding the advantage between thisembodiment and the first or second embodiment is that, in thisembodiment, it is possible to dramatically shorten the process cyclebecause the heating and cooling processes are not required. In addition,if the ultraviolet permeable member is used as the laminate member 8,this embodiment can be applied to the three-layer structure as discussedin the third embodiment wherein the intermediate layer 18 is used.

FIG. 18 is a schematic view showing a structure of a laminate unifyingapparatus used for a manufacturing method of a plastic laminate body ofa sixth embodiment of the present invention. Here, a three-layerstructure of the honeycomb-shaped substrate 9 discussed in the thirdembodiment, the laminate member 8, and the intermediate layer 18, arediscussed. A high frequency generation apparatus 22 is connected to theupper mold member 6 and the lower mold member 2 so that an electricalcurrent having a frequency higher than 1 MHz can be applied. Structuralmembers of the honeycomb-shaped substrate 9 and the laminated member 8fixed to the lower mold member 2 are formed under conditions that amultiplied result of a dielectric constant ε and a dielectric tangent δthereof is smaller than 0.01, namely ε×tan δ<0.01. Also, structuralmembers of the intermediate layer 18 are formed under conditions that amultiplied result of a dielectric constant ε and a dielectric tangent 6′of the intermediate layer 18 is larger than 0.01, namely 0.01<ε′×tan δ′,preferably larger than 0.05, namely 0.05<ε′×tan δ′. For example, as thestructural members of the honeycomb-shaped substrate 9 and the laminatedmember 8, a polyethylene terephthalate resin, polystyrene resin,polyethylene resin, polyetherimide resin, polyphenylene ether resin, orthe like, is used. As the structural members of the intermediate layer18, a polyvinyl chloride resin, methacryl resin, polycarbonate resin,ethylene vinyl acetate copolymer resin, or the like, is used. In thisembodiment, the polyetherimide resin is used for the honeycomb-shapedsubstrate 9, the polyethylene terephthalate resin is used for thelaminated material 8, and the ethylene vinyl acetate copolymer resin isused for the intermediate layer 18.

Next, an operation in the sixth embodiment is discussed. First, thehoneycomb-shaped substrate 9 is inserted between the intermediate layer18 and the upper mold member 6. See FIG. 18-(A). Next, the upper moldmember 6 is lowered down in a state shown in FIG. 18-(A). At this time,as in the third embodiment, the film-shaped laminate member 8 is pushedwith pressure by the honeycomb-shaped substrate 9 so as to have a curvedsurface configuration. Next, the laminate member 8 comes in contact withthe transfer surface 1 of the lower mold member 2. Finally, two members,namely the honeycomb substrate 9 and the laminate member 8, arepressurized and bonded. See FIG. 18-(B). Next, a high frequencyelectrical current is applied by the high frequency generation apparatus22. After a cooling process is done at a temperature that is lower thanthe softening temperature of the intermediate layer 18, the upper moldmember 6 is raised so that the unified laminate body 7 is picked out.See FIG. 18-(C).

Next, an advantage of the sixth embodiment of the present invention isdiscussed. According to the sixth embodiment of the present invention,as well as the third embodiments, it is possible to ease the pressuredistribution generated at the time of pressurizing by the escape of theexcessive resin of the laminate member 8 to the opening part 10 or thinwall part 12 of the honeycomb-shaped substrate 9, and thereby transferwith high precision can be realized. Furthermore, a substrateconfiguration can be corrected by melting the intermediate layer 18 sothat the transfer surface 1 can be transferred precisely.

Furthermore, in the sixth embodiment, if a high frequency electricalcurrent is applied, an intensive movement of a dipole inside of theplastic member occurs so that the plastic member itself self-heatsbecause of friction heat of the movement. The heat value of this case isin proportion to sizes of the dielectric constant ε and the dielectrictangent δ that are values of physical properties peculiar to members.

In this embodiment, structural members of the intermediate layer 18 areformed under conditions that a multiplied result of a dielectricconstant ε′ and a dielectric tangent δ′ of the intermediate layer 18 islarger than 0.01, namely 0.01<ε′×tan δ′, preferably larger than 0.05,namely 0.05<ε′×tan δ′. Because of this, it is possible to selectivelyheat the intermediate layer 18 without heating the laminated member 8and the honeycomb-shaped substrate 9. That is, in this embodiment, sincethe intermediate layer 18 alone can be selectively heated and heatresponse is extremely speedy, it is possible to extremely shorten theprocess cycle. Furthermore, in this embodiment, unlike the fifthembodiment, there is no limitation of structural members of the moldmember, and therefore it is possible to select a proper member byconsidering the strength as a mold member.

The high frequency heating way of this embodiment can be applied to thetwo-way structure as shown in the first and second embodiments byforming the laminate member 8 with structural members under conditionsthat a multiplied result of a dielectric constant E and a dielectrictangent δ is larger than 0.01, namely 0.01<ε×tan δ.

The present invention can be applied in a case where a mirror surface isformed with high precision as the transfer surface 1 and a case where aminute pattern is formed.

FIG. 19 is a schematic view of a rear projection type image displayapparatus having the plastic reflection mirror shown in FIG. 16. Asshown in FIG. 19, by applying the large size curved surface mirror(projection mirror) manufactured by the method of this embodiment to arear projection display, it is possible to spread the optical path sothat a thickness t of the rear projection can be reduced.

Furthermore, by using the large size curved surface mirror manufacturedby the method of this embodiment, it is possible to make a thin typerear projection display (rear projection type image display apparatus)shown in FIG. 19 having a high quality image. Here, in FIG. 19, anumerical reference “31” represents an optical engine formed by acrystal liquid panel or a projecting lens, and a numerical reference“32” represents a screen.

The present invention is not limited to these embodiments, butvariations and modifications may be made without departing from thescope of the present invention. For example, although thehoneycomb-shaped substrate and the porous body are discussed as anexample of the escape part in the above mentioned examples, otherstructures can be applied as long as the escape part can be formed. Inaddition, although the opening part of the honeycomb-shaped substrateshown in FIG. 7 has a square configuration, the opening part may have aconfiguration of a round shape, elliptic shape, polygon or regularpolygon such as a rectangular shape, triangle, rectangle, pentagon,hexagon, or the like.

This patent application is based on Japanese Priority Patent ApplicationNo. 2003-077198 filed on Mar. 20, 2003, and Japanese Priority PatentApplication No. 2003-378557 filed on Nov. 7, 2003, the entire contentsof which are hereby incorporated by reference.

1. A method of manufacturing a plastic laminate body, the plasticlaminate body having at least one plastic laminate member that islaminated on a plastic substrate, which plastic substrate ispre-processed in advance so as to have a substantially finalconfiguration, the manufacturing method comprising: softening theplastic laminate member when a transfer surface of a mold member, whichis pre-processed in advance so as to have a desired configuration, istransferred to a surface of the plastic laminate member, so that anexcessive part of the plastic laminate member is moved to an escape partwhich is pre-formed at the plastic substrate, wherein a metal reflectionfilm is pre-formed on a surface of the plastic laminate member.
 2. Amethod of manufacturing a rear projection type image display apparatus,including: a plastic laminate body which is used as a projecting mirror,the plastic laminate body having at least one plastic laminate memberthat is laminated on a plastic substrate, which plastic substrate ispre-processed in advance so as to have a substantially finalconfiguration, the manufacturing method, comprising: softening theplastic laminate member when a transfer surface of a mold member, whichis pre-processed in advance so as to have a desired configuration, istransferred to a surface of the plastic laminate member, so that anexcessive part of the plastic laminate member is moved to an escape partwhich is pre-formed at the plastic substrate, wherein a metal reflectionfilm is pre-formed on a surface of the plastic laminate member.